तद्बुद्धयस्तदात्मानस्तन्निष्ठास्तत्परायणाः। गच्छन्त्यपुनरावृत्तिं ज्ञाननिर्धूतकल्मषाः ॥

tad-buddhayas tad-ātmānas tan-niṣhṭhās tat-parāyaṇāḥ gachchhantyapunar-āvṛittiṁ jñāna-nirdhūta-kalmaṣhāḥ

Thinking on That, merged in That, established in That, solely devoted to That, they go whence there is no return, their sins dispelled by wisdom.

In plain words: Krishna says that people who keep their minds on God, give themselves fully to God and rest in God reach a state they never fall back from. Their wisdom has washed away their wrongs.